Grandma's Salad Dressing

This isn't my Grandma's recipe- I got it from a cooking class I took at BYU-Idaho.

Grandma's Salad Dressing
1/2 cup vegetable oil
1/4 cup and 2 Tbsp white wine vinegar
1/2 cup white sugar
1/2 onion, chopped
1/4 cup ketchup
1/4 tsp worcestershire sauce
Combine all ingredients in a large jar with a tight fitting lid. Shake until the sugar is dissolved. Refrigerate and shake well before using.